Two Kinds of Very High Energy Cosmic-Ray Stars

Abstract

40 30 ^)20 10 0 % \ \. X* FEf^ll PLOT OF dn"* (39.5 m) v i E0* 1.26 ±.01 M«V-N^O FIG. 2. Fermi plot of Sn 123 data. FB is the Coulomb factor calculated by means of Bethe's formula.spectrum, there is the line of internal conversion electrons corresponding to a gamma-ray energy of 0.153±0.005 Mev. The decay period of this line was followed and found to be 39.5 min.In a separate experiment, coincidences were observed between the internal conversion electrons and the beta-particles. The existence of such coincidences eliminates the possibility that the 0.153-Mev gamma-ray might correspond to a transition feeding the 130-day isomeric state of Sn m . Instead, the gamma-ray apparently follows the beta-decay and corresponds to an undelayed transition to the ground state of Sb 123 . Although some uncertainty exists because of absorption in the counter window and in the source, from the relative areas under the momentum distribution curve, one obtains for the ratio of internal conversion electrons to beta-disintegrations a value of 0.12. From the coincidence measurements, using a U3O8 standard to determine counter efficiency and geometry, the ratio was found to be 0.11. Figure 2 shows a Fermi plot of the beta-spectrum of Sn 123 . The deviation from a straight line at low energies arises from the use of a relatively thick source. The extrapolated end point is 1.26 ±0.01 Mev. The data in the immediate vicinity of the end point would have to be corrected for the resolution in order to fall on the straight line.The momentum distribution of the beta-rays of Sn 121 is shown in Fig. 3. No internal conversion electrons were observed. Absorption measurements also indicated that there is no gammaradiation present. It appears, therefore, that the beta-transition is directly to the ground state of Sb m . Figure 4 shows a Fermi plot of the data obtained with two different resolutions of the spectrometer. The extrapolated end point is 0.383±0.005 Mev. The fall-off at low energy is, of course, due to the absorption in the counter window. FIG. 4. Fermi plot of Sn*2i. 0.7 04 ^ 0.3 02 0.1 0 T FERMI PLOT Of \ ' \ \ 3%-V-6% Eo*0.383±.005 MC \ 1.4 W We should like to thank Mr. R. J. S. Brown and Mr. L. M. Baggett for assisting with the measurements. * This document is based on work performed under government contract number W-7405-Eng-36 for the Los Alamos

Emploi des émulsions photographiques pour la détection et l'étude des phénomènes nucléaires. Historique, résultats et possibilités. Bibliographie

“…70 Existence probable d'un méson 't plus lourd que les mésons x [41], ce qui confirme des observations antérieures à la chambre à détente [42], [43].…”

“…Ces émulsions sont appelées, assez incorrectement, « émulsions sensibles aux électrons ». Cet important progrès dans la technique entraîne une suite de travaux scientifiques, j'en citerai quelquesuns : 10 Existence de nombreux Inésuns chargés dans les explosions nucléaires causées par les particules cosmiques [63]. 20 Confirmation du fait que les électrons produits dans la désintégration des mésons :J. ne sont pas n1onoénergétiques [64] : deux particules neutres, au moins, sont émises dans cette désintégration, en plus de l'électron.…”

Collimated and Wide-Angle Meson Groups in a Hard-Shower Star

“…Collimated and Wide-Angle Meson Groups in a Hard-Shower StarMAURICE M. SHAPIRO Nucleonics Division, Naval Research Laboratory, Washington, D. C. AND HERMAN YAGODA National Institutes of Health, Laboratory of Physical Biology, Experimental Biology and Medicine Institute, Bethesda, Maryland August 10, 1950S PRAYS of relativistic particles associated with cosmic-ray stars have been observed in ultrasensitive photographic emulsions by many workers [1][2][3][4]…”